IUD, period or pregnant?

So I got my IUD on 19 December 2017. After that, I had very heavy pains and bleedings for 2 weeks long. Then it all stopped and I was fine, but one week after that, the pain came back but even worse than before. I went to my GP and she was quite shocked to hear this, so she booked me a scan. One day after that appointment my period started and it wasn't like anything I had ever experienced before. Usually my period only lasts for 5 days but this one lasted 7 days. I bled a lot and the pain was terrible. After that period I had my scan and the doctor said there was nothing wrong with my IUD. He also couldn't see a baby or whatsoever. As you can imagine I was quite relieved!

Now the pain in my tummy has returned and I seriously don't know what to do about it. I have also been feeling very nauseous and dizzy. Besides that, I've been having some crazy mood swings and it's driving my insane. Last monday during dinner, the pain started once again and I walked to the medicin cabinet to get me some painkillers. As soon as I stood up, I felt like I had to go to the toilet immediately. I got dizzy and I felt so sick and the pain wouldn't stop. I threw up and I had to lay down for 15 minutes but after that I was completely fine again and I even finished dinner. This has never ever happened to me before.

My period is supposed to start in 2 days but I feel like I could be pregnant. I can't stop thinking about babies and stuff like that, which is so weird. My GP suggested not to have unprotected sex until I had the scan, so my SO and I used condoms in the meantime. After the scan, we stopped using the condoms and he came inside me once or twice. Is there any chance I could be pregnant or is this all caused by my IUD or period? Let me know in the comments!